Post by: kelly on July 01, 2003, 08:23:23 AM
Why the G5 Runs So Fast
http://new.lowendmac.com/myturn/03/0701.html
Post by: Mrious_be on July 01, 2003, 10:14:20 AM
so i stopped reading after a little.Let's just say that Apple have an awesome processor at it's hands now
Post by: krissel on July 01, 2003, 11:46:14 PM
If you can slog through it you will understand what they are saying about the two FPUs that have the ability to do more math per unit. But I also ran across some caveats that make me think that to fully take advantage of the speed of the G5 we will have to upgrade many of our applications to ones rewritten for the G5's different architecture.
Here are a few things to note:
*the larger cache line size (128 vs 32) will create a bubble effect with programs written to take advantage of the smaller size
*longer latency to memory
*increased latency to G5 Velocity engine pipeline
*no L3 cache (programs that were optimized to it will have to be reworked)
*small chunks of data are now inefficient and large chunks will have to be written for the L2 cache
I'm wondering how well older programs will do on the new hardware. I'm sure Apple chose the most updated of programs to test the new machines.
One other thing I found interesting on that page:
QUOTE
A new OSX API has also been proposed that will provide a superset of the existing Gestalt, sysctl, and _cpu_capabilities functionality. This API will be named OSSystemInfo and is scheduled to appear in Smeagol and Panther.
Smeagol???
Post by: sandbox on July 02, 2003, 02:42:44 AM
Aliases: Gollum, Trahald, Slinker, Stinker
Date of Birth: 2430 T.A
Race: Hobbit of the Stoor strain
Height: between 3-4 feet, when not hunched over
Date of Death: 3019 T.A.
Alignment: Evil
Smeagol / Gollumn transform
Technically Speaking
QUOTE
This build, code-named Smeagol, will run on the new chip but won't take advantage of many of its key features, including 64-bit support. Sources said Apple's goal for Smeagol is to deliver Mac OS X performance at least "on par" with what Jaguar could achieve on Motorola G4 chips running at the same speed; the move will allow Apple to ship the new hardware before Mac OS X 10.3, a k a Panther, can take advantage of all the new processor's capabilities.
Post by: giantmike on July 02, 2003, 08:42:25 AM
As for the increased latency, I could see that on the velocity engine, as that was added on at the end of the 970s production stage. However, increased latency to RAM makes no sense, as there is no L3 cache, which should shorten the time looking through cache, and the frontside bus and memory itself is so much faster.
As with any CPU, specific optimizations are needed if you want to get the most out of every clock cycle. However, with updated compilers, most programmers should just have to run their code through a new compiler, with the correct flags set, and they will get 90% of the optimizations for the G5. The remaining 10% would take hours of work, and in most cases, not be worth it.
Even without recompiles of the program, the G5s will still be wicked fast on all of the programs that run on today's G3 and G4 computers.
Post by: krissel on July 02, 2003, 10:23:06 PM
QUOTE
DCBZ in the G5 has three detrimental effects on the performance of existing programs...
QUOTE
As the CPU frequency has increased at a much faster rate than the memory frequency, the relative time to access memory has increased in the G5 vs. the G4.
QUOTE
Avoid small data accesses. Due to the increased latency to memory, the longer cache lines, and the nature of the CPU-to-memory bus, small data accesses should be avoided if possible. The entire system architecture has been designed to optimize the transfer of large amounts of data (i. e. maximize system memory throughput). As a side effect, the cost to handle small accesses can be very high and is quite inefficient. If possible, allocate data in large chunks to better amortize the overhead to access memory. Adjust to the smaller cache. High-performance programs that have tuned themselves for the presence of an L3 cache will need to be re-worked to fit in the (now larger) 512 KB L2 cache.
I realize this article is to developers to warn them about the changes they should consider in new code. I imagined a long pronounced rewrite process necessitating new upgrades and consequent costs to the consumer. But I wasn't aware that a simple recompiling of already existing apps would basically eliminate or minimize these problems.
That's good to know.
Post by: () on July 07, 2003, 11:48:03 PM
Thanks for the information, very nice to read about the processors on the G4 and G5 as well as the P4.i am on a imac G4 and was wondering if I need to upgrade to a G5, but would rather see if there will be a G5 chip to have installed on my G4.
If you have any info about upgrading G4's to a G5 let me know.
Luv ya!
Post by: sandbox on July 10, 2003, 01:34:40 AM
Mac OS X 10.3 Panther will not be a 64-bit OS
By Tony Smith
@ The Register
Post by: kelly on July 10, 2003, 09:34:43 AM
The Power of the G5 and the Future of the Mac
http://new.lowendmac.com/musings/03/0710.html
Post by: Bill on July 10, 2003, 11:33:33 AM
QUOTE(sandbox @ Jul 9 2003, 11:34 PM)
a bit more on the topic.......
Mac OS X 10.3 Panther will not be a 64-bit OS
By Tony Smith
@ The Register
Mac OS X 10.3 Panther will not be a 64-bit OS
By Tony Smith
@ The Register
Got fleas hatching on the right coast SB?
With the heat on the left, they're as big as dogs. <gr>
Post by: kelly on July 14, 2003, 07:58:16 PM
Things I didn't know. Of course that covers a lot.
"... a dual, unidirectional bus.".
http://www.macopinion.com/columns/engine/0...7/10/index.html
They need to get these out to see what they're really like.
Post by: Bill on July 14, 2003, 08:18:42 PM
"Agreed.
Here's one on opinionated testing tactics.
QUOTE
If there's ever been a personal computer that everyone's gotta get, it's the Apple Power Mac G5.
QUOTE
Unfortunately, it appears that Apple has stolen a particularly tainted page from traditional PC vendors. Once, Steve Jobs marketed the Mac as the tool for individualists (think 1984's Super Bowl commercial) and then, for people who had some intellectual capacity (the Think campaign) and eventually, as a computer that simply worked without headaches and aggravation (the switch campaign), Apple now is taking on the PC industry with "benchmarketing."
It's right out of 1992, when PC vendors pumped up their efforts to cheat on benchmarks to claim a meaningless performance edge over a competitor. Sad to say, those benchmark shenanigans worked to a degree. For example, all the popular video card companies that remain today at one time exploited loopholes in benchmark design.
It's right out of 1992, when PC vendors pumped up their efforts to cheat on benchmarks to claim a meaningless performance edge over a competitor. Sad to say, those benchmark shenanigans worked to a degree. For example, all the popular video card companies that remain today at one time exploited loopholes in benchmark design.
eweek
Post by: Bill on July 31, 2003, 11:48:47 PM
More
the inquirer
Post by: kelly on August 01, 2003, 10:31:08 AM
Whatever.
They need to get them out so people can see how a Dual G4 1.4 GHz
compares to the G5 1.8 for example.
And which should you buy.
There's not much doubt the Dual G5 2 GHz will smoke.
Post by: Bill on August 01, 2003, 05:35:02 PM
Had to read that twice.
Post by: sandbox on August 02, 2003, 11:05:47 PM
Post by: Bill on August 03, 2003, 08:35:30 PM
No one, repeat no one could folk-tung his way through all of that.
Post by: Bill on August 06, 2003, 09:03:57 PM
Post by: Gary S on August 06, 2003, 09:18:33 PM
I'm waiting for the G6.
Post by: kelly on August 06, 2003, 10:02:32 PM
technology officer" would say such a thing.
Post by: Bill on August 07, 2003, 03:15:49 PM
Didn't read the other larger story from the other link though.